Karen completed her undergraduate degree in Chemistry and Mathematics at the University of St Andrews, where she was awarded the Charles Horrex prize for best undergraduate physical project. She then undertook her PhD with Professors Sharon Ashbrook and Philip Lightfoot, also at the University of St Andrews. Her thesis focused on the synthesis and structural characterisation of novel perovskite-based materials using a combination of powder diffraction, solid-state Nuclear Magnetic Resonance (NMR) spectroscopy and first-principles Density Functional Theory (DFT) calculations. Following her PhD research, she undertook post-doctoral work with Professor Robert W. Schurko at the University of Windsor, Windsor, Ontario, Canada. Here she focused on the development of wideline solid-state NMR techniques for the study of quadrupolar nuclei in transition-metal organometallic complexes. She also worked on the development of indirect detection methods for the study of nitrogen-containing pharmaceuticals. This was completed in collaboration with Professor Marek Pruski at The Ames Laboratory, Iowa State University. Karen then completed a second post-doctoral position in the Advanced Lithium Storage-European Research Institute (ALISTORE-ERI) with Dr Nicolas Dupré (Nantes, France) and Professor Clare P. Grey (Cambridge). Here she focused on the characterisation of ternary alloys for use as negative electrode materials in lithium-ion (Li-ion) batteries.
Her current research aims to combine high-resolution powder diffraction (X-ray and neutron) with multinuclear solid-state NMR and first-principles DFT calculations to study structure in the solid state. We are interested in the characterisation of both ordered and disordered materials. Current areas of interest include high temperature ceramics, e.g., perovskite-based systems. We are also interested in conversion materials for use as negative electrodes in Li- and Na-ion batteries. One area of particular interest is the design, synthesis and characterisation of novel solid electrolyte materials for use in both Li- and Na-ion batteries. Understanding the local structure of these materials will provide detailed insight into the physical properties they exhibit.
The Bigger Picture: Structural Insights into Functional Materials using Diffraction, Solid-State NMR and First-Principles DFT Calculations
The term “functional material” has been applied to a large array of compounds, including metals, metal oxides, semiconductors and zeolites. The range of exploitable properties available in functional materials is substantial and includes magnetism, dielectric properties, piezoelectricity and ionic conductivity. The range of possible application sectors is similarly large, with uses in energy generation and storage, transport, information and technology etc. As a result, functional materials have gained huge economic significance over the last 50 years.
Piezoelectrics and batteries are just two examples of functional materials studied extensively in recent years. Perovskites are an important class of materials that have been studied for use in both batteries and piezoelectrics. The alkaline niobates, NaNbO3, KNbO3 and the solid-solution KxNa1−xNbO3 (KNN) are of considerable interest owing to recent reports of exceptional piezoelectric responses, believed to be comparable to those of the most widely used piezoelectric ceramic, Pb(ZrxTi1−x)O3 (PZT). The work presented here focuses on the room temperature phases of NaNbO3, which remain a subject of considerable discussion. Several phases have been suggested and observed experimentally, including the antiferroelectric Pbcm and polar P21ma polymorphs of NaNbO3. The relative quantities of these two phases are known to vary considerably depending on the precise synthetic conditions used, e.g., conventional solid state techniques versus softer routes such as sol-gel. X-ray diffraction and solid-state NMR data will be presented comparing different synthetic techniques.
The rechargeable Li-ion battery has revolutionised global communication and is now considered the technology of choice for energy storage in portable electronic devices and zero emission vehicles. Conversion type materials have recently been suggested as plausible alternatives to conventional electrode materials. The ternary alloy TiSnSb was
recently proposed as a possible negative electrode material due to its excellent electrochemical performance. TiSnSb is known to undergo a conversion reaction, leading to the simultaneous formation of Li-Sb and Li-Sn intermetallic compounds. Several phases have been successfully identified via X-ray diffraction and 119Sn Mössbauer studies. However, several ambiguities remain. Can 7Li solid-state NMR provide insight into the phases formed during lithiation?